1. Field of the Invention
This invention relates to an improved quick connector for piping. A detachable universal joint (coupling) for piping (whose representative examples include a one-touch coupler and a quick coupler) will be referred to as xe2x80x9cquick connector in this specification.
2. Description of the Related Art
One known quick connector for piping is disclosed in Japanese Utility Model Unexamined Publication No. Hei. 6-28485 entitled xe2x80x9cQUICK CONNECTORxe2x80x9d.
FIG. 7 is across-sectional view of the conventional quick connector for piping according to the above publication, and this quick connector for piping 100 serves to detachably connect a male member 102 to a female member 101.
The female member 101 comprises a socket housing 104, in which an O-ring 105, a collar 106 and an O-ring 107 are inserted in this order, and a socket cap 108 in which a retainer 109 is movably received. The socket cap 108 is threaded on the socket housing 104 through a bushing 111.
The male member 102 comprises a pipe-like member, and has a projection 102a formed on an outer surface of an intermediate portion thereof, and this projection 102a is adapted to be fitted in the retainer 109 of the female member 101.
Next, the operation of the quick connector for piping will be described.
FIGS. 8A and 8B are views explanatory of the operation of the conventional quick connector for piping according to the above publication.
In FIG. 8A, the male member 102 is connected to the female member 101 through the O-ring 105. This O-ring 105 serves to prevent a fluid from leaking through a gap between the female member 101 and the male member 102, and those regions (4 regions), indicated by sign X in FIG. 8A, are seal portions.
In FIG. 8B, when the quick connector for piping 100 is mounted on a vibratory body such as a vehicle, the male member 102 is repeatedly moved relative to the female member 101 in the direction of the axis of the quick connector for piping 100 by the vibration as indicated by arrow b1. When the male member 102 thus moves in the axial direction, the male member 102 carries the O-ring 105 in the axial direction. As a result, torsion and a depression develop in the O-ring 105, which can adversely affect the performance of the seal between the female and male members 101 and 102.
It is therefore an object of this invention to provide a quick connector for piping in which torsion and a depression are prevented from developing in an O-ring, thereby ensuring a high reliability of the quick connector.
The above object has been achieved by a quick connector for piping of the invention for detachably connecting a male member to a female member, wherein an O-ring is interposed between the female member and the male member so as to form a seal therebetween; and the O-ring is subjected to a low-friction treatment so that the O-ring can be moved in a direction of an axis of the quick connector by a pressure of an employed fluid.
The male member is connected to the female member through the O-ring, so that the O-ring forms a seal between the female member and the male member.
The O-ring is subjected to the low-friction treatment so that the O-ring can be moved in the direction of the axis of the quick connector by the pressure of the employed fluid. When the pressure of the employed fluid acts on the O-ring, the O-ring is pressed in one direction (the direction of the axis of the quick connector). The O-ring is subjected to the low-friction treatment, and the pressure of the employed fluid acts on the O-ring, and therefore even when the male member is moved relative to the female member in the axial direction, the male member will not carry the O-ring. Therefore, the O-ring is kept stationary in a predetermined position regardless of the movement of the male member.